"Apparently, somebody was looking at the gun. That gun did discharge and one person was struck," said Sergeant Candi Baker of the Adams County Sheriff's Office.

The Tanner Gun Show bills itself as the state's largest gun show with 700 tables displaying guns, knives, ammunition, reloading equipment, military surplus and hunting and fishing gear.

The show, which drew fire in 1999 when three guns bought there were used by Dylan Klebold and Eric Harris in the Columbine High School shooting, has run in some form since 1964, The Denver Post reported.

It's not the first time there's been a shooting at or around the show - a 64-year-old Littleton man accidentally shot himself in the stomach with .38-caliber handgun in the parking lot in 2008.